Stock prices fluctuation analysis of food companies after the Great East-Japan Earthquake: Application of random matrix theory

Just after the Great East-Japan Earthquake in Fukushima on March 11th, 2011, in many Japanese companies, stock prices were declining. However, on the other hand, some companies' stock prices rose owing to the emergency demands of the earthquake. When we have been conducting the stock price fluctuations, we found the special pattern of a growth by the emergency demand of food companies. The companies are Otsuka Holdings, Toyo Suisan, and Nisshin Food Holdings. The companies produce emergency food such as pot noodles and CalorieMate. We infer that the rapid growth of the demand for the emergency food let the stock price risen. We analyze the stock prices using the Random Matrix Theory. The main part of the method is Singular Value Decomposition. We extract eigenvectors which are principle components of the time series data. In our analysis method, first we start at the landmark company and then using the company we in turn find other companies which have similar movement to the start company. In this paper, we shall describe the extracting approach of the special growth companies.